开始对每个请求进行C#WebClient NTLM身份验证

Question

考虑一个简单的C#NET Framework 4.0应用程序，该应用程序：

• 使用WebClient
• 使用NTLM进行身份验证（在IIS 6.0和IIS 7.5服务器上测试）
• 使用DownloadString()
多次从URL检索字符串

这里有一个很好的示例：

using System;
using System.Net;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string URL_status = "http://localhost/status";

            CredentialCache myCache = new CredentialCache();
            myCache.Add(new Uri(URL_status), "NTLM", new NetworkCredential("username", "password", "domain"));

            WebClient WebClient = new WebClient();
            WebClient.Credentials = myCache;

            for (int i = 1; i <= 5; i++)
            {
                string Result = WebClient.DownloadString(new Uri(URL_status));
                Console.WriteLine("Try " + i.ToString() + ": " + Result);
            }

            Console.Write("Done");
            Console.ReadKey();
        }
    }
}

Answer 1

经过10天的尝试，我能想到的一切，并在这个过程中学到了很多，我终于找到了解决这个问题的方法。

诀窍是启用UnsafeAuthenticatedConnectionSharing，方法是重写GetWebRequest，并在返回的httpWebRequest中将属性设置为True。

您可能希望将其与ConnectionGroupName属性结合使用，以避免未经身份验证的应用程序可能使用该连接。

using System;
using System.Net;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string URL_status = "http://localhost/status";

            CredentialCache myCache = new CredentialCache();
            myCache.Add(new Uri(URL_status), "NTLM", new NetworkCredential("username", "password", "domain"));

            MyWebClient webClient = new MyWebClient();
            webClient.Credentials = myCache;

            for (int i = 1; i <= 5; i++)
            {
                string result = webClient.DownloadString(new Uri(URL_status));
                Console.WriteLine("Try {0}: {1}", i, result);
            }

            Console.Write("Done");
            Console.ReadKey();
        }
    }

    public class MyWebClient : WebClient
    {
        protected override WebRequest GetWebRequest(Uri address)
        {
            WebRequest request = base.GetWebRequest(address);

            if (request is HttpWebRequest) 
            {
                var myWebRequest = request as HttpWebRequest;
                myWebRequest.UnsafeAuthenticatedConnectionSharing = true;
                myWebRequest.KeepAlive = true;
            }

            return request;
        }
    }   
}